Inherently processable interpolymers of vinyl chloride, a higher alkyl acrylate, andan acrylic nitrile



Patented Aug. 26, 1952 INHERENTLY PROCESSABLE 'INTERPOLY- MERS ,OF VINYL CHLORIDE, A HIGHER AIZKYL ACRYLAIE, AND AN ACRYLIC NITRILE .;Robert.J. Wolf-sand, Anthony A. Nicolay, Cleveland, ,0hio,=-ass ignors to TheQB. F. Goodrich :Jlompany, .NewrYork, N; Y. a, corporation of .rNevrYork No Drawing. ApplicationFebruary:1,;1950,

:Serzial No...-141*,'862

3.Claims.

1 :Ihepresentinvention relates tointerpolymers obtained byv :the" polymerization of monomeric mixtures containing at least three monomeric acumponents; eachin particular proportions, one --foiwhichis:vinyl-chlorideanother of which is" a ihigher 1 alkylacrylate su'ch as an octyl'tacrylate, and? a third of which is a 'nitrile of an acrylic acid :suclr-as acrylonitrile; 'methacrylonitrile and the ..-like; which interpolymerspossess various new and areful properties, especiallyinregard to their exxcellent:- strength; resistance tothe effects 'oflight and :heat, good low: temperature flexibility, and .zresistancmto-the.effects .of fatsv and oils; and :it pertains more specifically to three component-invital-polymers.or tripolymers of these three types of;

amonomers -which-areclear, strong, tough, and .c-flexlble yet are :processable :withoutthe addition i-of'plasticizers. I

Vinyl resinssuch as polyvinyl-chloride, and co- ..adhesive bondbetween the-surface one plasticized vinyl resin composition'and-another surfatedae- .cause the oilyplasticizer migrates tothe adhesive epolymers of vinyl chloride with variousnotherirzo vfore, toprovidea newclass of, vinylre'sins each member of which is, possessed of manyoi thencmonoolefinic-monomers such as :vinylidene chloeride, vinyl-acetate-,..methyl.acrylate, acryonitrile -..-anddiethyl fumarate .are well knownvto the art earewidely usedin various .familiar applications.

lniising. such resinsitis thepractice to first-mii-rgzd 'thethermoplastic resin, which by itself is nor-' mally hard andhorny at normal temperatures and isgenerally, incapableof. being easilysubj ecteditoprocessingor forming operations, with con- ;isi'derablequantities of. liquid plasticizers such asi30 complete absorption of the plasticizer by'the resinjfforiiinarily .called jfplasticization of thejj resin) have a 'strong'tend'ency to'jbleed.or migrate to the "surface 'of'the'resincomposition where they are, lost through wiping," washing orvolati-lization,

Fwimathe resum that" theficompositidn gradually sti-fiens as the pla'stlcizerisrem'oved until a point is reachedwhere thecompositionfails'bytearing, "cracking'etc. Underexposure to hot soapy water as is' encoiintered by plastic sh'ower'curf tains, reblecicjthsg baby pants-and thelike, the I 'oily -plasticizer is extracted bythe 'soapywater at --i aigreatlyfiaccelerateirratesuchthat the composi- :Jtiombecomes and-useless in an unduly aishortwtime. J-OtI'IeriIIefectS rot plasticized" vinyl include:thdifllcultydn achieving ala'sting layerand destroys .the bond. Varnishedbrlac- .queredsurfaces arealso marred .ion rprolonged -contractwith an article madeciplasticized yiriyl .resin because the thin. .film of .plasticizenalways present on the plastic. articles isnalsora soitener for thelacquen orv varnish resin. "A .iurther disadvantage is that only. plasticizers mustlnormally be incorporated into a vinyl resin by aneexpensiye and .timeeconsuming .milling or, operation. I I r .A still further limitation ofeknewnplasticized resincomposi-tions is .the fact that whenplasti- .cized with. sufficient. -plasticizernto be- .easily processed, they. are .insufficiently, .strong,.-,.tongh and rigid atnormal .temperaturestdbeaiseim a .number-oiimportantapplications It is. a primary, object of this. invention, .theresirable properties possessedbyknown vinyl resins and plasticized vinyLresin compositionhanilnin addition, is so inherentlyprocessable thatvthe additionof extraneous plasticizers is not regiiired either for processing or. for good plasticproperties. in thefinal product, and .which .on.that;a ,c-

count can be employed to.produce numerons articles which aremore durable, serviceablegand otherwise more desirablethan similar arti'cleslof conventional vinyl resins. 'It, is. also an. object to provide new vinyl resins which .are proces sable .without plasticizer and which at normal tempera- .tures possess improved toughness and strength, thereby to be. useful over a, wider range;,of;applications than conventional 'plasticize'd Lvinyl .resins. The achievement of these and still other obj ectiveswill become apparent in the. description of the invention which follows.

We have found that by polymerizing, preferably in an aqueous medium, monomeric mixtures containing at least three components, each in definite proportions, one being vinyl chloride, another'an ,alkyl acrylate the alkylgroup of which from 5 to 10 carbon atoms, preferably arr-*octyl acrylate, and a third a, nitrile of anacrylicaicid such as acrylonitrile, we are able toobtain-novel interpolymers having the properties necessa'iwtor achieving the above and other objectives? f The relative proportions of the three types-"oi monomers in the monomeric mixture employed in the production of our new 'interpolymers are somewhat critical, since 'the desired properties are'not secured with these 'monomers in alh promade up of these three ingredients. ot her mono manner, although polymerization in an aqueous medium is greatly preferred. Polymerization in an aqueous emulsion, whichniay cit-may not contain an added emulsifying agent,'is offcourse essential when a latex of the in'terpolymer is the"- desired end-product. ferred method, the mixture of monomers mays be. polymerized by the pearl type suspension olefinic monomeric materials such as vinylidene chloride, diethyl maleate, styrene, isobutylene, the lower alkyl acrylates such as methyl and ethyl acrylate and others are, if desired, utilizable to the extent of by weight of the mixture. However, it is preferred that only monomeric materials of the three specified types be present. Particularly valuable as soft inherently processable materials are the tripolymers, that is,polymers made from three componet monomeric mixtures containing from 50 to 60% by weight of vinyl chloride, from 20 to 40% by weight of the jhigher -alkyl acrylate and from 2 to 20%, by fi wei ht of the acrylic nitrile. 1 ,Thefacrylie nitrile used in this invention may e any nitrile'of acrylic or an aloha-alkyl or ala halo acrylic acid among which are acrylonitril'e. niethacrylonitrile,"etha rvlonitrile, chlo- 1 oacrylonitri 1e,,etc. Acrylonitrile, by reason of "iit S'IOW cost and readv availabilitv and b reason f of its forming excellent interpiolymers with vinyl "chloride and the higher alkyl acrylates, is greatl'y preferred. i

'The hi her alkyl acr lates which are employed in this invention are those alkyl esters of acrylic acidjin which the alkylgroup contains a chain jo'f'from 5 to- 1 0 carbon atoms. We have found th t the degreefof plasticity or'inherent process- 1 lity; imparted to our new interpolymers' by these h gher alkyl acrylates is lar ely determined ,by t he length and configuration of the alkylgroup 4 the fa k l' acrylate and thatthisicorresponds .in a' qualitative manner with the'observed degree ffofplasticization imparted to ordinary vinyl resins ,by addition of ester-type plasticizers containing ".the same or similar alk l groups. For example, Idi-.2-ethylhe'xyl,phthalate is an excellent plasticizerifor vinyl chloride polymers and 2-eth lhexyl .acrylate has been found to produce interpolymers ,;with' vinyl chloride and acrylonitrile which are easily processed without plasticizer or without 'Qbeing heated to high temperatures. Illustrative {higher alkyl acrylates within the above class Z ntilizable in this invention are n-amyl acrylate. ln-he'xylv acrylate, isohexyl acrylates, isoheptyl acrvla'te, n-heptyl acrvlate, capryl acrylate (-1- mthyl-heptyl acrylate), n-octyl acrylate, 2-

1 'ethylhexyl acrylate, isooctyl acrylates such as 6- .r'nethyl-heptyl acrylate, .n-nonyl acrylate, isononyl acrylate, isononyl acrylates such as 3,5,5-

trimethylhexyl acrylate, n -decyl acrylate and others.

It is greatly preferred to employhigher alkyl {acrylates-in which the alkyl group contains a tot al ,of '8,to. 1 0 carbon atoms and possesses a ,-,-car bon chain ofj6 to-1O atoms. Compounds withnjthis class are 6-methylhepty1 acrylate, 3,5,5- tr-irriethylhex yl acrylate, 2-ethylhexyl acrylate, capryljacrylate (1-methylheptylj acrylate) npctyl acrylate and others- I The higher alkyl acrylates-of this class impart ahigh degree of inherent processability to our new interpolymers and the compound most efficient in this respect is n-octyl acrylate.

The polymerization'to form our new interpolymers maybe carried out in any conventional hyde resin or the like. By this method the interpolymer is obtainable in a fine granular form. The polymerization may also becarried out in Qthe presence of a solvent or diluent other than water. In the latter method the polymer is obtained either as a fine granular precipitate or as a "solution in the solvent depending on the dene compounds. Actinic radiationmay be employed, as well as the various peroxygen-compounds such as hydrogen peroxide, benzoyl peroxide, 0,0 -dichlorobenzoyl peroxide," 'caproyl peroxide, caprylyl peroxide, pelargonyl peroxide, cumene hydroperoxide, tertiary butyl hydroperoxide, l-"hydroxyc'yclohex'yl hydroperoxid'e', -te'r'tiary butyl diperphthalate', tertiarybutyl' p'erbenzoate, sodium, potassium and ammonium' prsmfate, sodium perbor'ate, sodium percarboiijatie and others. These "oxidizing catalysts reacli 'their fullest activity when used in om maudn wim a reducing substance-such as sodium"'su'lfite, so-

dium thiosulfate, a'pblyhydroxy phenolsuch as resorcinol or the like, in what 'is generallyfie v but. more useful latices are secured with :the

synthetic emulsifying agents including-the hy- 'ferred to as a redoxi polymerization; "Such polymerizations are often greatly activated by the presenceof a'small amountof a heavy metal salt such as silver nitrate, copper sulfate orvarious ferric and cobalt compounds andothers.

It may sometimes be desirable to control or ad- Just the hydrogen ion concentration of the polymerization mixture, which tends to become more acid during the .polymerizationdue'to liberation of HCl. It is preferred in' somecases, therefore, that there be added to the reaction mixture a buffering substance such as sodium bicarbonate, trisodium phosphate, ammonium hydroxide, sodium' hydroxide, the amino-substituted alcohols such as 2-amino ZemethyFI-propanol or the like.

Any of the usual emulsifying agentshm'ay ibe employed when the polymerization is. carried out in aqueous emulsion. Ordinary alkali-emetal,

ammonium andalkanolamine fatty-acid soapssuch as sodium .oleate, sodium myris'tate, pq iassium palmitate, ammonium 'stearate, ethan olamine laurate and the like 'as .well.as rosin'lor disproportionated rosin. acid soaps may be used,

v molal sulfates and sulfonates such as sodium laurylsulfate, sodium cetyl sulfateythe sodium salts of sulfonated parafiin oil,'the:so dium salts of dodecane-l-sulfonic acid, octadecane-l-sulfonic acid, etc.; alkaryl sulfonates such as the sodium alkyl benzene sulfonates, .sodium'isopropyl naphthalene sulfonate, sodium isobutyl In addition to this pre-- I .Polymerization was complete .onagitatiom vof-this tough but flexible, completely fused disc. By 'wayof comparison, unplasticized polyvinyl'chlo- -1 ride can notbeso press-molded and plasticized polyvinyl chloride containing :upto; 50 parts 1 of di:-2-ethy1hexyl phthalate' requires a molding mcycle of.,3minutes at 350 1 e The press-molded sheet of'tripolymerhad a hardness of .78 (Duro. A), a tensile strength-of 1-1600;lbs./sq. in., an elongation of .,310%:and' an lteAsTMbrittleness temperature. of.- 50 j The tripolymer of this 'EXampIeIII possessed a light stability when tested as in Example .I'of

95%;. It also showed great resistance to; high temperatures in, a heat'stability test similar to 3 r'the light stability. test; Thus,.the.per cent light transmission after exposure of the film-hior 24 hours :in' a mechanical convection air-ovenat 175"C'...was 92%; *In the .same test :polyvinyl cent light transmissionof ".chloride ishowed a; per

still another manner the surprising heat resistance of :the tripolymer of this Example III was demonstrated. When a plasticized vinyl :resincompositionis heated in. an air oven=for 168 hours ('7 days) at 100 C. the composition sufiers'a 5 -to 25%a'loss in we'ight .(loss of plasticizer or chemical breakdown or both"); 'a'permanent decrease in tensile strength and modulus at 100% elongation and either a great permanent decrease or increase in elongation. For I e'x ai nple'a sample of polyvinyl chloride plasti- Ycized with 35 parts of di-2-ethylhexyl phthalate and containing 2 /2% by weight on the polyvinyl chloride of a stabilizer consisting of .the mixed [cadmium salts of fatty acids and. naphthenic acids, sufiered after such heat treatment, a 5- to s decreasein weight, up to 100% decrease, in elongation and a decrease in 100% modulus of "30%. A sample of the tripolymer of Example I11, similarly stabilized, and similarly exposed to theheat treatment, however, showed a zero loss in weight and no change in tensile strength, elongation or modulus.

Example IV I Another tripolymer was produced by subjecting the following mixture to polymerizing'com dition's: I I

1Material: Parts/wt. Vin'yl chloride 55.0 2-ethylhexyl acrylate 40.0 Acrylonitrile 5.0 Potassium persulfate 1.3 Emulsifier (same as Ex. I) 4.0

NHa 0.2 Water 94 5 Polymerization was complete within 40 hoursat 50 C. The resulting latex contained about 50% total solids. The coagulated polymer formed a "c1e'ar,"soft and flexible, and completely fused disc after press-molding for only'l minute at 130 C.

' The tripolymer formed-a smooth band} without 'plasticizer, on a mill having its rolls maintained T at only 150 F. A sheet of the tripolymer pressmolded 3 minutes at 300 F. had a hardness of 70 (Duro. A) and had a surprisingly low ASTM brit- :,,tleness temperature of 70'i F.

318 3 i 5;J...17361171712918;.VF1;1 .55 V Aftripolymer"was madefby pol Ilia-rang the monomeric materials contained in a moiloi i ric Material: 3 j q Vinyl chloride -e esr 2 -ethylhexyl acrylate 10.0

Potassium pe sulfate 1.. Emulsifier-(same as Ex, I)

C. with-the production ofan' excellent white latex eomainmg 53.6% total" solids. The tripolymer obtained therefrom was casement being milled, molded, and extruded without'plasticizerf :It 'had a, lightstability 'o f 80% and a'heat Stability 0f 90%. A molded disc' of the tripolymer w'as hard and stifrfi yet was clear and smooth- I 1 Another tripolymerwas prepared byfpolymerizing the monomericjmaterials' containedin the fo11owing.mixture:

liM i a 1 a e/w Isononyl acrylate "hours at 50 C'. 'The"resultingtripolymer had j a hardness of Ql Duromet erA, a tensile strength of 2200-lbs./st1. in., an" elongation of 400%, and a, l00%'modulusof 1600 lbs;/s'q.in. The ASTM brittleness temperature of the tripolymerwas F. This ftri'polymer was capable of being -milled without plasticizer at 150 R; of being extruded without"plasticizer at 240 "F and'of being 'calendered without .plasticizer; at, 210 1F.

- Polyvinyl: chloride; plasticized to -a similar hardness requires millingtemperatures.oi 280 to300 extruding temperatures of 30.0 to 400 and calendering temperatures of at least 340F.

T Examples VII. t0 IX Three monomeric mixtures, the first containing by weightof vinyl chloride, 25% of'2- styrene were polymerized in thei recipe 0t Example I 'to produce in each cas'efan interpolymer' in latexform. The latex of the '60/2 5/10/5 tetrapolymer containing ethyl acrylateyformed and its light stability 95%.

a good filmwhen heated .toonly100or. 150 C. The heat stability of this tetrapolymerwas 66% The-:/30/5 tripolymer had a milling-temperature of;150 F.,

l a, tensile strength of 2100 lbs/sq; in.,-an elongation o f 2 50%, a modulus at 100% elongation of 1000 lbs/sq. in., and a hardness Of 6 5 (Duro.

Y o). The 55/15/10/10 tetrapolymer containing 'styreneformed goodfilms at 150, C. and had a light stability of 90%.

While the invention 'has be'en' described with T particular. reference to certain preferred embodiments thereof, it is possible to make variations and modifications therein without departing from the spirit and scope of the invention as defined in the appended claims.

We claim:

1. An interpolymer made by polymerizing a mixture of monomeric materials comprising from 50 to 60% by weight of vinyl chloride, 20 to 40% by weight of an alkyl acrylate in which the alkyl group contains from to carbon atoms, and from 2 to by weight of an unsaturated nitrile selected from the class consisting of the nitriles of acrylic acid, alpha-alkyl acrylic acids and alpha-halo acrylic acids, at least 90% by weight of said mixture being made up of the enumerated ingredients.

2. A tripolymer made by polymerizing a mixture of monomeric materials consisting of from 50 to 60% by weight of vinyl chloride, 20 to by weight of an alkyl acrylate in which the alkyl group contains a total of 8 to 10 carbon atoms and possesses a carbon chain of 6 to 10 carbon atoms, and 2 to 20% of acrylonitrile.

3. A tripolymer made by polymerizing a mixture of monomeric materials consisting of from 10 to by weight of vinyl chloride, 20 to 40% by weight of 2-ethylhexy1 acrylate, and from 2 to 20% by weight of acrylonitrile.

ROBERT J. WOLF. ANTHONY A. NICOLAY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,140,043 Fikentscher et al. Dec. 13, 1938 2,462,422 Plambeck Feb. 22, 1949 2,486,241 Arnold Oct. 25, 1949 2,510,426 Smith June 6, 1950 FOREIGN PATENTS Number Country Date 685,257 Germany Dec. 14, 1939 OTHER REFERENCES Rehberg et al., article in Ind. Eng. Chem., August 1948, pages 1429-1433. 

1. AN INTERPOLYMER MADE BY POLYMERIZING A MIXTURE OF MONOMERIC MATERIALS COMPRISING FROM 20 TO 60% BY WEIGHT OF VINYL CHLORIDE, 20 TO 40% BY WEIGHT OF AN ALKYL ACRYLATE IN WHICH THE ALKYL GROUP CONTAINS FROM 5 TO 10 CARBON ATOMS, AND FROM 2 TO 20% BY WEIGHT OF AN UNSATURATED NITRILE SELECTED FROM THE CLASS CONSISTING OF THE NITRILES OF ACRYLIC ACID, ALPHA-ALKYL ACRYLIC ACIDS AND ALPHA-HALO ACRYLIC ACIDS, AT LEAST 90% BY WEIGHT OF SAID MIXTURE BEING MADE UP TO THE ENUMERATED INGREDIENTS. 